Electrical apparatus



Feb, 10, 1959 .J. F. KURTIS 2,873,326

ELECTRICAL APPARATUS Filed May 20, 1957 2 Sheets-Sheet 1 FIG. I

FIG. 2

INVENTOR.

JAMES F. KURTIS BY 7!. d. 3%

ATTORNEY Feb. 10, 1959 J. F. KURTIS 2,8 33

ELECTRICAL APPARATUS Filed May 20, 1957 2 Sheets-Sheet 2 Fl G. 3 4a )0 8a m. I g

JAMES F. KURTIS ATTORNEY FIG. 4

United States Patent ELECTRICAL APPARATUS James F. Kurtis, Niles, Mich., assignor to Koontz-Wagner lllgftric Co., Inc., South Bend, Ind., a corporation of n ana Application May 20, 1957, Serial No. 660,155

Claims. (Cl. 200-104) The present invention relates to electrical switches and more particularly to switches of the carbon break type. One of the principal objects of the present invention is to provide a compact, eiliciently operating and dependable electrical switch of the carbon break type.

Another object of the present invention is to provide a switch which is adapted to break a high current flow with a high inductive load and which will give optimum performance over long periods of time without servicing. In conventional carbon pile type switches the carbon elements are mechanically held together while the switch is closed and are urged and held apart by a spring or the like when the switch is opened. This type of switch breaks the current most efficiently when all of the contact points between the carbon elements are broken simultaneously. However, to obtain this type of operation the tolerances of the various elements must be closely maintained both in production and service; otherwise,

the circuit will be broken at one point rather than at all of the points simultaneously. This is particularly so when the switch is opened rapidly. It is therefore one of the primary objects of the invention to provide a switch having at least three carbon elements in series forming a multiple carbon contact structure which operates to break the current simultaneously at all the carbon contact points.

A further object of the present invention is to provide a switch of the carbon pile type having a positive means for separating the several carbon elements simultaneously.

Still another object of the present invention is to provide a relatively simple compact multiple switch unit for controlling a high and low current flow circuit, in which carbon pile contact points are used in the circuit of the high current ilow and metallic contact points are used in the circuit of the low current flow.

Another object of the invention is to provide a multiple throw solenoid operated switch which automatically adapts itself to the solenoid plunger adjustments to give dependable continuous trouble free service.

Another object of the invention is to provide a switch for controlling the operation of a solenoid requiring a high operating current and a low hold current, which can readily be built as an integral part of the solenoid unit.

Additional objects and advantages of the present invention will become apparent from the following description and accompanying drawings, wherein:

Figure 1 is a longitudinal cross sectional view of a solenoid switch combination, the switch portion shown in elevation;

Figure 2 is an end view of the unit shown in Figure 1;

Figure 3 is a longitudinal cross sectional view of the switch shown in elevation in Figure 1;

Figure 4 is a cross sectional view of the switch shown in Figure 3 taken on line 4-4 of said figure; and

Figure 5 is an electrical wiring diagram for the solenoid and switch shown in the preceding figures.

Referring more specifically to the drawings, numeral 10 designates a solenoid, 12 a switch for controlling the operation of the solenoid, and 14 a housing into which the solenoid and switch are built as an integral unit. For the purpose of the present description the solenoid may be considered as a conventional unit having an electrical coil 16 and a plunger 18 adapted to reciprocate in the coil, said plunger having a stem or shaft 20 joined integrally with the right hand end thereof, as seen in Figure l, for engaging and operating some other mechanism or device (not shown), a hole 21 being provided in the free end of the shaft for connecting it to the mechanism or device. The plunger is urged to the right against an end cap 22 threadedly mounted on end plate 23 of the housing, by a coil spring 24 reacting between the outside surface of end cap 22 and a washer 26 held firmly by said spring against a collar 28 seated in and held against longitudinal movement by an annular groove in shaft 20. A flexible cap 30 of rubber or the like is placed over the spring 24 and sealed to shaft 20 and cap 22 to prevent moisture and dirt from entering the housing around the shaft. The small end of cap 30 has an annular flange 31 which is clamped between washer 26 and collar 28 and is held firmly in place by the force of spring 24 on the opposite side of the washer. The large end of cap 30 has a relatively thick internal flange 32 for seating in an external annular groove 34 in end cap 22 and forming a fluid tight seal therewith.

The coil is connected to connector 40 by a lead 42 and to switch 12 by a lead 44, said leads forming a part of the circuitry shown in the wiring diagram of Figure 5. From this diagram it is seen that lead 44 forms a part of both the energizing and, the hold circuits, the latter circuit including a resistor 46, a lead 48 connecting lead 44 with the resistor and a lead 50 connecting the resistor with connector 40. Lead 42 is connected with line 52 in which a master control switch 54 is located and lead 50 is connected with return line 56. The holding circuit, which is controlled solely by switch 54 and is closed throughout the continued operation of the solenoid, provides only sufiicient current to hold plunger 18 to the left, as seen in Figure 1, against the force of spring 24 urging the plunger to the right. In order to move plunger 18 to the left in opposition to spring 24 the energizing circuit is employed consisting of leads 42, 44 and 58, stationary contact 59, movable contact 60, stationary contact 61, and leads 62 and 50. As plunger 18 completes its stroke to the left, it moves contact away from contacts 59 and 61, opening the energizing circuit and leaving further operation and control of the solenoid to the holding circuit controlled by switch 54.

A signal circuit for indicating at a remote panel that the solenoid is energized is also controlled by switch 12 and consists of contact 64 connected to lead 50 by lead 66 and a light 68 connected to contacts 64 and 69 and by leads 70 and 72 and to line 52 by lead 74. Movable contact 60 closes contacts 69 and, since the movable contact 60 which operates both switch units 64 and 69 is operated by the solenoid through a one-way connection including a stem 76, a spring 78 is provided for moving I the contact in the right hand direction as seen in Figures 1, 3 and 5, when the solenoid is deenergized.

The solenoid is separated from the switch in housing 14 by an annular pole piece 80 having a reduced diameter portion 82 extending into the coil and having a hole 84 therethrough in which stem 76 reciprocates as it is operated by the solenoid. Switch 12 which is cylindrical in shape is secured to pole piece 80 by a plurality of screws 86 extending longitudinally therethrough into the pole piece which in turn is secured in place in the housing by a suitable set screw, pin or the like 87. The switch is enclosed in the unit by a cup shaped cover 88 sealed to the body of the housing and retained in place by screws 86 extending through the end of the cover and through spacers 89. Fins 90 are provided on the external surface of the cover to dissipate the heat generated by the switch and resistor 46. Since the present switch and solenoid combination is designed for use under severe operating conditions including extreme variations in temperature, humidity and polluted atmosphere, the entire combination is constructed as a hermetically sealed unit.

Referring to Figures 3 and 4 which show a specific embodiment of the present invention, stationary contacts 59 and 61 consisting of semi-disc shaped carbon elements are seated in recesses in a mounting board 92 of nonconduction material such as plastic or hard rubber, which holds the carbon elements firmly in a fixed position in the switch and fully insulates the carbon elements from the rest of the switch except on the side contacted by movable contact element 60. The mounting board has a central stem 94 formed integrally with the disc portion of the board and having a longitudinal hole 96 therethrough. The stem fits snugly into a central cylindrical recess in pole piece 86 in which central hole 84 communicates with hole 96 of stem 94. The carbon elements 59 and 61 are connected into the solenoid energizing circuit by leads 58 and 62, respectively, having their ends 98 and 99 embedded in the elements to form good electrical connections with the carbon.

Movable contact element 60 consists of a disc shaped carbon element mounted in a metal retaining cup 191 on stem 102 rigidly connected to the disc portion of the cup and extending through the greater part of hole 96. Contact elements 59 and 61 are insulated from stem 102 by an annular sleeve 103 formed in effect as an extension of stem 94 and, from each other, by partitions 104 and 106 formed as an integral part of the mounting board. A sealing ring 107 is mounted on said stem in an annular groove 108 and, to provide insulation between stem 102 and stem 76, a plastic insert 109 i mounted in a recess in the end of stem 102. If the master control switch 54 is closed the solenoid energizing circuit is closed when disc shaped carbon element 60 is in direct contact with semi-disc shaped carbon elements 59 and 61, the current then flowing from lead 53 through contacts 59, 60 and 61 to lead 62. The energizing circuit is broken when the solenoid is energized and stem 76 carried by plunger 18 engages the right hand end of stem 102 and moves the stem together with cup 1% and carbon disc contact '60 to disengage it from contacts 59 and 61.

In the signal or auxiliary circuit, contacts 64 and 69 are connected to leads 66 and 70, respectively, by terminals 119 and 112 and are closed in the switch by a thin disc shaped metal plate 113 of coin silver mounted on cup 100 on the side opposite carbon contact 60 and insulated from said cup by a disc of insulating material 114 interposed between the plate and cup. The two terminals are mounted in a cylindrical body member 115 of electrical non-conducting material secured against riounting board 92 by screws 86 and consist of a threaded portion to which leads 66 and 70 are attached and yieldable contact points 64 and 69 urged toward plate 113 by a coil spring 116 and 118, respectively, in cylindrical receivers 120 and 122. The movement of points 64 and 69 toward plate 113 is limited by a flange 124 abutting against the end of-the respective recesses, so that said points are spaced from the plate when the carbon switch is closed. The resistor 46 of the solenoid holding circuit is wound on the periphery of member 115. The points are made yieldable so that close adjustment in the final travel of the solenoid plunger and stem 76 is not required in that any over-travel is absorbed by springs 116 and 118 after points 64 and 69 have been contacted by plate 113.

A shaft 126 seated in a central recess in stem 162 and having a reduced diameter portion forming apin-like extension 128 provides an insulating support for the plate. It is thus seen that the assembly forms two independent movable contacts for the stationary contacts 59 and 61 of the solenoid energizing circuit and for stationary contacts 64 and 69 of the signal circuit. Movable contact 60 is constantly urged in the direction to close the carbon contacts 59 and 61 by spring 78 which reacts between the bottom of recess 130 in member and plate 113.

In the operation of the switch and solenoid which have been installed as a unit for operating some other mechanism or device through shaft 20, switch 54 is closed, closing the circuit through solenoid 10, carbon contacts 59, 60 and 61 having already been closed by spring 78. On energization of the solenoid, plunger 18 moves to the left until the end abuts against the end of pole piece 8% As the plunger approaches the end of its travel, stem 76 carried by the plunger engages the end of stem 1G2 and moves carbon contact 60 away from contacts 59 and 61, thus interrupting the solenoid operating current. The solenoid, however, remains energized and the plunger is held in its left hand position by the current through the holding circuit including resistor 46, until manually operated switch 54 is again opened. Further movement of stems 76 and 102 after the carbon switch has been opened causes plate 113 to engage the ends of contacts 64 and 69 closing the circuit to signal light 68 which thereafter remains lighted as long as the solenoid is energized. The holding circuit is closed by switch 54 and remains. closed until this switch is again opened. When switch 54 is opened the solenoid is deenergized, permitting spring 24 to return plunger 18 and stem 76 to their full right hand positions and permitting spring 78 to shift the movable switch member to the right to open contacts 64 and 69 and engage carbon disc 60 with carbon contacts 59 and 61. With the carbon contact switch closed the energizing circuit is ready for operation whenever switch 54 is again closed.

Although the solenoid shown and described is operated on D.-C. current, the switch covered by this application is suitable for use in either D.-C. or A.-C circuits. In some installations electrical conducting materials other than carbon for contacts 59, 60 and 61 and metal for contacts 64, 69 and 113 may be used satisfactorily if desired. Various other changes can be made without departing from the scope of the invention.

I claim:

1. An electrical apparatus, comprising a solenoid having a reciprocal core, a circuit for said solenoid a circuit for a signal light, a switch mechanism in said circuits including a pair of fixed semi-disc shaped members composed of carbon and being spaced from one another, leads in said solenoid circuit connected to said members, a disc shaped means having an axial shaft thereon with a longitudinal hole therethrough for retaining said members in fixed position, a cup shaped member having an axial stem thereon extending through the hole in said shaft and reciprocating therein, said last mentioned member having a disc shaped carbon contact on one side thereof adapted to contact said members, two spaced contacts connected to said signal circuit, springs for urging said contacts toward the other side of said last mentioned member, a metal disc element on said other side of the last mentioned member adapted to engage said two s'pacedcontacts, a means operated by said solenoid for opening said carbon switch and closing said spaced contact switch, and a spring for closing said carbon switch and opening said spaced contacts.

2. An electrical apparatus, comprising a solenoid having a reciprocal core, a circuit for said solenoid, a circuit for a signal light, a switch mechanism in said circuits including two stationary carbon contacts, leads in said solenoid circuit connected to said contacts, a disc shaped means having an axial shaft thereon with a longitudinal hole therethrough for retaining said contacts in a fixed position, a cup shaped member having an axial stem thereon extending through the hole in said shaft and reciprocating therein, said last mentioned member having a disc shaped carbon contact on one side thereof, two spaced contacts connected to said signal circuit, a metal element on the other side of the last mentioned member adapted to engage said two spaced contacts, and a means operated by said core for engaging said stem and moving said cup shaped member between said carbon contacts and said spaced contacts.

3. An electrical apparatus, comprising a solenoid, a circuit for said solenoid, a second circuit, a switch mechanism in said circuits including two stationary carbon contacts, leads in said solenoid circuit connected to said contacts, a disc shaped means having an axial shaft thereon with a longitudinal hole therethrough for retaining said contacts in fixed position, a cup shaped member having an axial stem thereon extending through the hole in said shaft and reciprocating therein, said last mentioned member having a disc shaped carbon contact on one side thereof, two spaced contacts connected to said second circuit, a metal element on the other side of the last mentioned member adapted to engage said two spaced contacts, and a means operated by said solenoid for engaging said stem and moving said cup shaped member between said carbon contacts and said spaced contacts.

4. An electrical apparatus, comprising a solenoid, a circuit for said solenoid, a second circuit, a switch mechanism in said circuits including two stationary carbon contacts, leads in said solenoid circuit connected to said contacts, a carbon disc adapted to move axially to and from said contacts to control the circuit for said solenoid, two spaced contacts connected to said second circuit, a metal element movable with said carbon disc, and a means operated by said solenoid for moving said carbon disc and metal element alternately between said spaced contacts and said carbon contacts.

5. A switch, comprising semi-disc shaped members composed of carbon and being spaced from one another, a disc shaped means having an axial shaft thereon with a longitudinal hole therethrough for retaining said contacts in fixed position, a cup shaped member having an axial stem thereon extending through the hole in said shaft and reciprocating therein, said last mentioned member having a disc shaped carbon contact on one side thereof, two spaced contacts, springs urging said contacts toward the other side of said last mentioned member, a disc element on said other side of the last mentioned member adapted to engage said two spaced contacts, and means for engaging said stem and moving said cup shaped member between said carbon contacts and said spaced contacts.

6. A switch, comprising two stationary carbon contacts, a disc shaped means having an axial shaft thereon with a longitudinal hole therethrough for retaining said members in fixed position, two spaced contacts, a cup shaped member between said stationary and spaced contacts having an axial stem thereon extending through the hole in said shaft and reciprocating therein, said last mentioned member having a disc shaped carbon contact on one side thereof, a metal element on the other side of the last mentioned member adapted to engage said two spaced contacts, and means for engaging said stem and moving said cup shaped member between said carbon contacts and said spaced contacts.

7. A switch, comprising two stationary semi-disc shaped elements composed of carbon and being spaced from one another, a disc shaped means having an axial shaft thereon with a longitudinal hole therethrough for retaining said elements in fixed position, a cup shaped member having an axial stem thereon extending through the hole in said shaft and reciprocating therein, a disc shaped carbon element supported by said member for contacting said elements, and means for moving said member toward and away from said first mentioned elements.

8. An electrical apparatus, comprising a solenoid, a circuit for said solenoid, a pair of fixed semi-disc shaped members composed of carbon and being spaced from one another, leads in said solenoid circuit connected to said members, a disc shaped means having an axial shaft thereon with a longitudinal hole therethrough for retaining said members in fixed position, a cup shaped member having an axial stem thereon extending through the hole in said shaft and being adapted to be operated to actuate said apparatus.

9. A switch, comprising two stationary contacts, a disc shaped means of insulating material having an axial shaft thereon with a longitudinal hole therethrough for retaining said contacts in fixed position, two spaced contacts, a cup shaped member between said stationary and spaced contacts having an axial stem thereon extending through the hole in said shaft and reciprocating therein, said last mentioned member having a disc shaped contact on one side thereof, an element of electrical conducting material on the other side of the last mentioned member adapted to engage said two spaced contacts, and means for engaging said stem and moving said cup shaped member between said first mentioned contacts and said spaced contacts.

10. A switch, comprising two stationary elements spaced from one another, a disc shaped means having an axial shaft thereon with a longitudinal hole therethrough for retaining said elements in fixed position, a cup shaped member having an axial stem thereon extending through the hole in said shaft and reciprocating therein, an element supported by said member for contacting said elements, and means for moving said member toward and away from said first mentioned elements.

References Cited in the file of this patent UNITED STATES PATENTS 978,377 Humphrey Dec. 13, 1910 1,000,934 Ostermann Aug. 15, 1911 1,240,351 Little Sept. 18, 1917 1,522,546 Richmond Jan. 13, 1925 1,765,381 Menzel June 24, 1930 2,127,887 Rayburn Aug. 23, 1938 2,180,661 Baruch Nov. 21, 1939 2,381,075 Nelstm Aug. 7, 1945 2,435,484 Wellman Feb. 3, 1948 2,650,970 Gauvreau Sept. 1, 1953 

